That's actually me.
Completely stock exhaust, I tape a lapel mic to the diffuser and run the cable through the car to the camera. That's why the exhaust sounds good because the mic is right next to it

This should be mandatory reading for anyone that wants to put an aftermarket exhaust on their car for noise reasons. The car sounds different from inside the car than it does outside! If you make your car sound from the inside the way you want it to sound from the outside, what you have done is made your car extremely annoying to 99.9% of the people that will hear it.